The push-push type latch device latches the movable body such as a lid and the like to the main body at the fixed position (usually, a closed position) of the main body by a push operation against an urging force of an urging means, and by the next push operation, the above-mentioned latching is released. This latch device excels in usability in that both the latching and releasing can be carried out by the push operation to the movable body; however, in a latched state, if the movable body receives the inertial force accompanied by a sudden stop and the like, it happens that the latch device can be moved in a direction same as the push operation at the time of the release, so that there is a possibility of being released from the latching by an operation error. As a measure against this, there are two major types of the latch device: an inside installation type (for example, Japanese Patent No. 2912433) wherein a safety function is added to the latch device itself, and an exclusive type which is independent from the latch device exemplified in Japanese Patent Document 1 and the like. Incidentally, compared to the exclusive type, the inside installation type is easily limited in safety performance or accuracy by the relation of disposing structural members inside a latch case.
FIGS. 12(a), 12(b) show a safety device of Japanese Patent Document 1, FIG. 12(a) shows a state in which the inertial force is not applied, and FIG. 12(b) shows a state in which the inertial force is applied. This overall structure comprises a housing H whose left side is open; a movable body (storage box) B; urging means which is not shown in the figures and urges the movable body B in an open direction; and push-push type latch device which is not shown in the figures. By the above-mentioned latch device, the movable body B is latched to a blocked position of the housing H by the push operation against the urging force, and by the next push operation, the latching of the movable body B is released, so that the movable body B can move in the open direction of the housing H.
The safety device has a structure of being provided with a rotational body 1 pivotally supported at an axis member 3 in the housing H and urged in one direction through a spring 2; and an inertial responding-body 4 which can be varied between a standby position and an operation position. Also, a projection allowing the rotational body 1 to rotate in an opposite direction against the urging force of the spring 2 is provided when a blocked state of the movable body B itself is released. Only when the inertial force acts, the inertial responding body 4 is moved in the operation position, and the rotation in the opposite direction of the rotational body 1 is halted. In other words, in this structure, when the inertial force is applied, the movable body B is pushed in an arrow direction due to inertia in the same way that the inertial responding body 4 is projected against the urging of a coil spring 6 as in FIG. 12(b) due to the inertia. Even if the rotational body 1 is attempted to be rotated clockwise against an urging pressure of the spring 2, the rotational body 1 hits the inertial responding body 4, which is projected due to the inertia, so that the rotational body 1 cannot rotate. Thereby, the movable body B is halted so as not to move in the same direction to release the latching of the latch device through the projection 9 which is controlled by the above-mentioned rotational body 1.    Patent Document 1: Japanese Utility Model Publication No. H05-75003